PLEDM (phase-state low electron drive memory) is a new memory microchip technology that offers vastly greater capacity than memory devices commonly used in the past. The images and sound for a full-length movie can be stored on a single PLEDM device. Because the memory is nonvolatile memory (data remains when power is removed), PLEDM chips, which contain no moving parts, offer the possibility of replacing the electromechanical disk drives familiar to today's PC users.
The first PLEDM chips, developed in 1999 at Hitachi's laboratory at the University of Cambridge, had a read/write time of less than 10 nanoseconds (10-8 seconds). In the future, these chips promise to combine the high speed currently available with DRAM (dynamic random-access memory) and the nonvolatility of so-called flash memory. It is envisioned that the chips could also be used in mobile and portable telephone sets and in digital video recorders. Ultimately, this technology might lead to single-electron memory (SEM), in which each data bit is determined by the presence or absence of one electron in an atom or at a particular energy level within an atom.
Products using PLEDM are expected to become available at the consumer level by 2005.